Digestible Energy Requirements For Maintenance Research Articles

Elevated nitrate levels affect the energy metabolism of pikeperch (Sander lucioperca) in RAS

The increasing demand for pikeperch (Sander lucioperca) from recirculating aquaculture systems (RAS) has raised the need for detailed knowledge on water quality parameters. Nitrate thresholds are of interest as nitrate accumulates in RAS and influences fish physiology. The trial was conducted in a recirculating aquaculture respirometer with pikeperch (average body weight (BW) 367 ± 1.1 g) successively reared at three different nitrate-nitrogen (NO3–N) concentrations (N30: 30 mg L−1, N120: 120 mg L−1 and N240: 240 mg L−1) and compared to a control group reared at the lowest possible nitrate-nitrogen concentration (N0: 5 mg L−1). Pikeperch were fed once per day with a commercial diet at three different feeding levels corresponding to 0.3% BW, 0.6% BW and 0.9% BW in triplicates for 8 days at either nitrate-nitrogen concentration before fasting for additional 3 days. Oxygen consumption and ammonia excretion were measured for 22-h in fed and fasting pikeperch to examine the influence of nitrate on energy metabolism. Metabolisable energy, retained energy and digestible energy requirements for maintenance (DEm) as well as the efficiency for energy utilisation (kg) and relative protein utilisation for energy metabolism (as ammonia quotient (AQ)) were determined. Specific dynamic action (SDA) was calculated to estimate the amount of energy spend on ingestion, digestion, absorption and assimilation of feed at different nitrate levels. SDA was significantly increased in the N240 treatment. Results of DEm showed a significant difference between N30 and N120 with DEm of N120 being about 73% higher than DEm of N30. The efficiency kg was significantly decreased between N240 and both N120 and N30 by 10% and 11% respectively. Increased values in AQ in the feed depleted fish in the N240 treatment indicates that fasting pikeperch in the high nitrate treatment had to use body protein to fuel an average of 46 ± 7% of their energy metabolism. The results of this trial show that pikeperch tolerate NO3–N concentrations of up to 240 mg L−1 but energy requirements are most favourable at concentrations of 30 mg L−1 NO3–N.

Digestive physiology of the plains viscacha (Lagostomus maximus): A large herbivorous hystricomorph rodent.

Plains viscachas (Lagostomus maximus) are large South American, fossorial rodents susceptible to diabetic cataracts. Various aspects of their digestive physiology were studied in three different experiments with nine male and seven female adult animals and six different diets (total n of feeding trials = 35). Viscachas achieved mean retention times of 23–31 hr, which is of a magnitude also recorded in horses; these did not differ for solute or small particle (<2 mm) markers. Secondary marker excretion peaks indicated coprophagy, and were rarer on high-protein as compared to grass hay-only diets. Mean resting metabolic rate was, at 229 kJ/kg0.75/day, lower than expected for a mammal of this size. Digestible energy requirement for maintenance was 445 kJ/kg0.75/day. At 1.6–2.7 L/day, viscachas produced more methane than expected for a hindgut fermenter of their size. On diets that included concentrate feeds, viscachas excreted glucose in their urine, corroborating reports on the susceptibility of this species for diabetes when kept on energy-dense food. Viscachas had a similar apparent digestibility of protein, lipids, and macrominerals as other rodents, rabbits, or domestic horses. This suggests that whether or not a species practices coprophagy does not have a major influence on these measures. Viscachas resemble other hindgut fermenters in their high apparent calcium digestibility. With respect to a digestibility-reducing effect of dietary fiber, viscachas differed from rabbits and guinea pigs but were similar to horses, suggesting that small body size needs not necessarily be linked to lower digestive efficiency on high-fiber diets.

Effects of diet-induced weight gain on insulin sensitivity and plasma hormone and lipid concentrations in horses

To determine the effects of diet-induced weight gain on glucose and insulin dynamics and plasma hormone and lipid concentrations in horses. 13 adult geldings. Horses were fed 200% of their digestible energy requirements for maintenance for 16 weeks to induce weight gain. Frequently sampled IV glucose tolerance tests were performed before and after weight gain to evaluate glucose and insulin dynamics. Adiposity (assessed via condition scoring, morphometric measurements, and subcutaneous fat depth) and plasma concentrations of insulin, glucose, nonesterified fatty acids, triglycerides, and leptin were measured on a weekly or biweekly basis. Mean + or - SD body weight increased by 20% from 440 + or - 44 kg to 526 + or - 53 kg, and body condition score (scale, 1 to 9) increased from 6 + or - 1 to 8 + or - 1. Plasma glucose, triglyceride, and nonesterified fatty acid concentrations were similar before and after weight gain. Leptin and insulin concentrations increased with weight gain. Mean + or - SD insulin sensitivity decreased by 71 + or - 28%, accompanied by a 408 + or - 201% increase in acute insulin response to glucose, which resulted in similar disposition index before and after weight gain. Diet-induced weight gain in horses occurred concurrently with decreased insulin sensitivity that was effectively compensated for by an increase in insulin secretory response. Obesity resulted in hyperinsulinemia and hyperleptinemia, compared with baseline values, but no changes in lipid concentrations were apparent. Preventing obesity is a potential strategy to help avoid insulin resistance, hyperinsulinemia, and hyperleptinemia in horses.

Energy and nitrogen partitioning in 250 g Atlantic cod ( Gadus morhua L.) given graded levels of feed with different protein and lipid content

The effects of feed intake level on energy and nitrogen partitioning were studied in juvenile Atlantic cod (250 g) fed two fish meal based diets differing in protein and lipid content (54:31 and 65:16) at 10 °C. Replicate groups of cod were feed deprived for 32 days or fed one of the two diets at 25, 50, 75 or 100% of group satiation for 60 days. Feed intake and oxygen consumption were measured daily and weights and chemical composition of carcass, liver, viscera and whole body were measured at start and end. Diet digestibilities were assessed in a separate experiment. The whole body and carcass growth rates at a given feed intake did not differ between dietary groups, but the liver grew faster in the fish fed the low protein diet, resulting in higher hepatosomatic indices at the end of the experiment in the groups fed this diet. The efficiency of utilisation of digestible nitrogen for growth ( k DNg) was higher for the low protein diet (0.73 ± 0.02) than for the high protein diet (0.53 ± 0.05), resulting in higher nitrogen retention at a given nitrogen intake. No difference in percentage nitrogen retention was seen in full-fed fish however (31.2 ± 2.5 and 28.4 ± 1.6% for the low protein and high protein diets, respectively). This can be explained by higher nitrogen intake in the fish fed the high protein diet, resulting in a smaller proportion of the intake being used for maintenance. There was no difference in energy utilisation between dietary groups. The digestible energy requirement for maintenance (DE maint) was 53.8 ± 0.9 kJ kg − 1 d − 1 (42.3 ± 0.7 kJ kg − 0.8 d − 1 ) and the utilisation efficiency for growth ( k DEg) was 0.80 ± 0.02. The energy retention in full-fed fish was 31.3 ± 3.5 and 31.7 ± 1.0% for the low protein and high protein diets, respectively. The deposited energy was distributed in approximately equal proportions in the liver and carcass, whereas viscera accounted for a minor proportion. At a given energy intake, the fish fed the high protein diet deposited more energy in the carcass and less in the liver than did those fed the low protein diet.

DIGESTIBLE ENERGY REQUIREMENTS FOR MAINTENANCE OF BODY MASS OF WHITE-TAILED DEER IN SOUTHERN TEXAS

Abstract Previous experiments designed to estimate daily digestible energy requirements for body-mass maintenance in white-tailed deer (Odocoileus virginianus) were conducted using deer adapted to northern environments. However, animals adapted to warmer, drier environments may have lower metabolic requirements than their temperate conspecifics. We conducted a feeding trial to estimate digestible energy requirements for maintenance of body mass of white-tailed deer in southern Texas and to determine if those requirements vary over time. By restricting dietary levels of digestible energy and measuring deer body mass every 3 days for a 30-day period, we developed a model relating digestible energy intake and change in body mass over time for 11 adult, nongravid females during autumn. Predicted daily digestible energy intake requirements for body-mass maintenance (kJ/kg body mass0.75) ranged from 820 ± 168 SE at trial initiation to 357 ± 42 at trial completion. Our experiment demonstrated that daily digestib...

Nutritive value and palatability of guajillo ( Acacia berlandieri) as a component of goat diets

Guajillo ( Acacia berlandieri Benth.) is a low-growing, multi-stemmed shrub widely distributed in southern Texas and northern Mexico. Proximate analysis indicates the leaves have high concentrations of nitrogen and energy suggesting that it is a potentially valuable forage resource, yet excessive consumption is believed to cause a hind-limb ataxia. The nutritive value of, and their preference for, guajillo leaves was determined in two trials using male Angora goats (8 months old, 23.7±1.09 kg initial weight). In a metabolism trial, air-dried guajillo leaves and alfalfa hay were chopped and mixed to prepare four diets containing 0, 25, 50 and 75% of guajillo leaves, which were fed in a 4×4 Latin Square design. Animals were retained in metabolism crates for a 10 day adaptation period followed by a 7 day collection period. Diets were analyzed for DM, OM, N, NDF, ADF, ADF-N, cellulose, lignin, gross energy, phenolic amines, and bovine serum albumin precipitating capacity. Feed DM and OM intake, water consumption, fecal and urine output, nitrogen and energy balance, and urine glucuronic acid output was determined on the animals. Dietary concentration of guajillo had no effect ( P>0.05) on intake (26.25±1.86 g OM kg −1 BW). Water intake and urine output decreased ( P<0.05) with increasing guajillo in the diets, but water retention increased ( P<0.05) with increasing guajillo. The digestibility of all the nutrients decreased ( P<0.05) with increasing level of guajillo, with ADF digestibility reduced to zero in the 75% guajillo diet. Energy balance and nitrogen balance expressed as percent intake decreased ( P<0.05) with increasing level of guajillo. Increasing ADF-N, together with reduced ADF digestibility, reduced the availability of nitrogen in the 75% guajillo diet. Phenolic amine and tannin concentrations increased ( P<0.05) as level of guajillo in the diet increased. Glucuronic acid output in goats fed 75% guajillo was significantly ( P<0.05) higher than the other diets, and suggests an increased requirement for liver glucose metabolism in goats consuming large amounts of guajillo. In the palatability trial, the same goats were fed 250 g of each diet for 9 days in a cafeteria trial to determine the characteristics eliciting a proportional choice among the four diets. Total DMI was similar to the results of the first trial. However, intakes of particular diets decreased ( P<0.05) with increasing level of guajillo. Despite an apparently desirable gross energy content of all the diets, those containing guajillo did not meet digestible energy requirements for maintenance and mohair production at moderate levels of activity and production, and although none of the diets appeared to be acutely toxic, the goats preferred the diets lower in guajillo.

Energy and protein utilization and partition in rabbit does concurrently pregnant and lactating

AbstractChanges in body composition during lactation in 40 primiparous rabbits were studied by comparative slaughter. The results were used to determine the utilization of digestible energy (DE) and digestible protein (DP) and their partitioning between maternal body, milk and foetal tissues.Twelve does were slaughtered immediately after their first parturition (first slaughter group) to estimate initial body composition. The 28 remaining does were remated 1 to 3 days after parturition and divided into two groups offered a pelleted diet at different levels: group L, fed ad libitum and group R, fed 0·75 of ad libitum. The 19 does that were pregnant (10 of L group, 9 of R group) were kept in individual metabolism cages until their second parturition. They were then slaughtered with their litters.Milk yield was higher (147·0 v. 117·2 g/day, P &lt; 0·02) and live-weight loss was lower (–42 v. –294 g) in group L than in group R. The food intakes were 304·7 and 234·4 g/day, respectively. Body composition of the does changed substantially between the first and second parturition, with a considerable loss of fat and some loss of protein. A large decrease in empty body (digesta-free body) weight was observed in both groups. The loss of energy corresponded to proportionately 0·32 and 0·41 of the initial body energy, in L and R groups respectively.The DE requirement for maintenance was estimated to be 468 kj/day per kg M0·75 and the efficiencies of utilization of DE and body energy for milk production were 0·63 and 0·76, respectively. The efficiency of utilization of DE for foetal tissue synthesis was estimated to be 0·27 throughout pregnancy. The DP requirement for maintenance was 3·80 g/day per kg M0·75 and the efficiency of utilization of DP for milk protein production was 0·76 and of body protein 0·61. The efficiency of utilization of DP for foetal protein synthesis was 0·46.

A field study to estimate the energy requirements of modern Belgian and Percheron horses

Summary Digestible energy requirements for maintenance and fattening of 14 mature, purebred Belgian and Percheron horses were estimated in a 98-day feeding trial. Horses were fed Bermuda grass hay and varying amounts of oats to achieve variation in weight change. The horses were weighed at weekly intervals, and the regression of weight on day of the trail was calculated to determine daily weight change. Digestible energy requirements for maintenance and fattening were estimated by regression analyses of digestible energy consumption vs. weight change. The estimated digestible energy required for maintenance was 27 kcal/kg body weight (144 kcal/kg75). The estimated digestible energy requirement for fattening was 16.02 Mcal/kg of gain.

Digestibility of timothy hay by African elephants

AbstractTwo juvenile, female African elephants (Loxodonta africana) were used in summer and winter trials to determine the apparent digestibility of timothy (Phleum pratense) hay. After 12–14 days of dietary adjustment, dry matter intake and fecal excretion were quantitatively measured for 7 days. Dry matter of timothy hay contained 8.6 and 7.7% crude protein, 57.3 and 44.0% acid detergent fiber, and 6.5 and 6.4% ash during the summer and winter trials, respectively. Estimates of apparent digestibility during summer and winter, respectively, were 39 and 35% for dry matter, 43 and 32% for gross energy (GE), 45 and 30% for crude protein (CP), and 36 and 24% for acid detergent fiber (ADF). While GE and CP digestibility estimates tended (P &lt; .09) to be greater in the summer trial, only the digestibility of ADF was different (P &lt; .05) between summer and winter. Dry matter intake was 1.4–1.6% of body weight (BW), providing an average of 144 kcal of digestible energy per kg BW0.75. This value is similar to that (155 kcal per kg BW0.75) used for estimating digestible energy requirements for maintenance of light‐breed horses.

The influence of energy intake and percentage of body fat on the reproductive performance of nonpregnant mares

Sixty mares in transition from winter anestrus to normal cyclicity were assigned to a 3 × 2 factorial experiment to determine the effect of energy intake and percentage of body fat on the interval to first ovulation. The factors were 1) percentage of body fat--thin (<11.5), good (11.5 to 15), or fat (>15); and 2) energy intake--maintenance (100% of National Research Council (NRC) digestible energy requirement for maintenance) or high energy (150% of NRC digestible energy requirement for maintenance). Percentage of body fat was estimated by ultrasonographic scanning of rump fat thickness. Energy treatments began on April 2 and ended on June 4. Mares were teased daily with a stallion and their ovaries were palpated per rectum daily or every third day. A high energy intake was effective in hastening ovulation for mares in the thin group (P < 0.05) but not for mares in the moderate or fat groups. Mares in the fat group had a shorter (P < 0.05) interval from April 2 to ovulation (26.4 ± 4.2 d) than those in the good or high energy-thin groups (48.7 ± 2.8 and 49.1 ± 4.2 d, respectively). Duration of the initial estrus was shorter (P < 0.05) for mares in the fat group (16.2 ± 5.7 d) compared with mares in the good group (34.7 ± 3.9 d) and tended (P<0.12) to be shorter than mares in the high energy-thin group (29.0 ± 5.7 d).

The influence of dietary protein and energy intake on the performance, body composition and energy utilization of pigs growing from 7 to 19 kg

ABSTRACTThirty-six entire male pigs were used to investigate the effects of two levels of dietary crude protein (150 and 220 g/kg) each in combination with four levels of feeding (1·0, 1·32, 1·64 MJ digestible energy/kg M0·73per day andad libitum) on growth, body composition and energy utilization over the live-weight range 7 to 19 kg.Growth rate responded linearly (P&lt; 0·001) to increasing energy intake but was depressed (P&lt; 0·05) when dietary crude protein was reduced from 220 to 150 g/kg.Raising digestible energy intake increased and decreased respectively the proportions of fat and protein in the empty body at 19 kg live weight. However, the magnitude of the response of both components to change in digestible energy intake was reduced in the case of pigs fed the lower protein diet.Total energy retained and that retained as fat and as protein responded linearly (P&lt; 0·001) to change in digestible energy intake of either diet. Extrapolation of the regression of total energy retained on digestible energy intake yielded a digestible energy requirement for maintenance of 510 kJ/kg M0·75per day, which was unaffected by level of dietary protein.The partial efficiencies of protein utilization, estimated from the regressions of protein deposition (g/day) on protein intake (g/day), were 0·616 and 0·411 for pigs given the diets containing 150 and 220 g crude protein per kg respectively.